sábado, 2 de agosto de 2014

Scientists have shown that human skulls changed in ways that indicate a
lowering of testosterone levels at around the same time that culture was
blossoming. Heavy brows were out, rounder heads were in. Technological
innovation, making art and rapid cultural exchange probably came at the
same time that we developed a more cooperative temperament by dialing
back aggression with lower testosterone levels.

A composite image shows the facial differences between an ancient modern
human with heavy brows and a large upper face and the more recent
modern human who has rounder features and a much less prominent brow.
The prominence of these features can be directly traced to the influence
of the hormone testosterone. Credit: Robert Cieri, University of Utah

Modern humans appear in the fossil record about 200,000 years ago, but it was only about 50,000 years ago that making art and advanced tools became widespread.

A new study appearing Aug. 1 in the journal Current Anthropology finds that human skulls changed in ways that indicate a lowering of testosterone levels at around the same time that culture was blossoming.

"The modern human behaviors of technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament," said lead author Robert Cieri, a biology graduate student at the University of Utah who began this work as a senior at Duke University... sciencedaily.com

Actualización: Did a Drop in Testosterone Civilize Modern Humans? | Psychology Today
The species we know as “anatomically modern humans” (Homo sapiens sapiens) dates
back to around 150,000-200,000 years ago. While ancient humans resemble
modern humans in their gross anatomy, they did not live anything like
we do now, nor even like our hunter-gatherer forebears did. From 200,000
years ago, to around 65,000 years ago, Homo sapiens was just
another hominin, barely distinguishing itself from the two or three
other hominin species that were living at that time (Neanderthals,
Denisovans, and isolated populations of H. floreseiensis and H. erectus surviving in some Pacific islands). Tools were crude; technology was scanty; culture was just beginning.

However, in Africa, around 65,000 years ago, humans' behavior
suddenly began to change toward what we call behavioral modernity.
Around this time, humans began fashioning much more advanced tools,
constructing more sturdy dwellings, donning elaborate clothing and
jewelry, and the signs of complex culture began to emerge...